The head louse is a long-known and rather specific human parasite. This insect "chose" for its habitation is the scalp, successfully infecting both adults and children, and therefore in general head lice are considered more common and numerous than other related species - pubic lice.
In addition to humans, head lice can not parasitize any other animals . The reason for this is a very high degree of fitness for lice to live and reproduce precisely on human hair, and this exceptional fitness is manifested both in the appearance of lice and in the characteristics of their biology as a whole.
Below in the photo - head lice close-up:
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The pubic louse in the past few decades has become quite rare, and many experts even believe that it can soon become a vanishing species. This is due to the improvement in the sanitary conditions of life for a growing number of people, as well as to the popularity of the "bikini" haircut on the pubic area, because of which lice, in principle, are deprived of their normal habitats. But the fashion for shaved heads is not particularly spread, and therefore a normal habitat for head lice is found almost everywhere where there are people.
An interesting evolutionary phenomenon was the emergence of a separate form of head lice, which moved to clothing, and the human body moves only for feeding - this is the so-called louse (otherwise - lingerie). For many centuries that people wear clothes, this form of parasite has managed to acquire some changes in the structure of the legs and the general way of life that allow it to feel great on clothes.
In laboratories, the head and head lice are able to successfully interbreed and give fertile offspring. However, under natural conditions on the human body, they are almost always isolated from each other, and therefore become less and less like one another.
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Separation of head lice into two forms is a unique precedent that allows scientists in real time to observe the process of formation of a new species of insects. Even more interesting is that it is the activity of a person and the appearance of clothing that is the main condition for the isolation of clothing lice. It is possible that head and ward lice will take quite a bit of time to become completely different species - in this case, one can safely say that a person with his own way of life involuntarily spawned a new parasite.
Knowing well how lice look on a person's head, one can be able to determine the presence of parasites even before they cause quite a lot of trouble. Below are several photos of head lice, as well as nits, which are usually the first to catch sight of the infected head:
"When the first time Dasha brought lice from school, I was shocked. At my very first time in my parents, my lice were taken out, but I thought today this problem is no longer relevant at all. It turns out that lousy children regularly appear in the school, especially after the summer holidays. The first few weeks of lice are not visible, and then the child begins to scratch his head, his white spots appear. This is a nit. And the child is embarrassed to say that his lice - everyone will laugh. These are usually not even allowed to go to school before they are cured. It's good that it's easy to get them out. I took MediFox, did everything according to the instructions, and combed Dasha's hair with a special comb for three more days. But if it happens somewhere in the village, then you need to use kerosene, which is dangerous - the child can damage his hair. It's good for parents with boys, they can just shave their baby's head, and all problems will be solved by themselves. "
How does the head louse look like: photos and pictures
The head louse is a small insect. The length of the body of an adult specimen is 2-4 mm, and in a nymph (the so-called larva of a louse) - from 0.7 to 2 mm. The lice have a light brown color, which allows them to successfully mask themselves on the scalp and in the hair.
Below the photo shows adult head lice and several eggs (nits):
After being saturated with blood, the body of the louse becomes red:
There are no wings in lice, and neither can they fly nor jump far. But while lice quickly enough move through the hair and the scalp, thanks to which, even with short contacts of hair, different people manage to move to a new victim.
"My Vanya picked up lice for the first time in two years - he did not go to the kindergarten and got infected, probably from one of the children on the street where we all walk together. I was already shaking all over when I saw them. Such filth! Still thought, what is it together with lice fleas sit - those, that white, are lice, and those which red are fleas. Only then it dawned upon me that the red ones were lice, only with blood in their stomachs. God, I had hysterics then, well, my mother-in-law was next to me, and calmed me, and quickly did everything - went to the pharmacy, bought chemically water and then myself sat in the bathroom with Vanya, while lice were poisoned ... "
Head lice have a rather characteristic body shape - an elongated abdomen and forelegs extended forward. With an unaided look, the lice on their heads look like small ants, but on closer examination it is clear that they have a more massive abdomen. In the photo below, you can see how the head louse looks when magnified under a microscope:
Larvae of lice (nymphs) are lighter and are characterized by translucent coverings of the body. Due to this, after saturation with blood in the center of their abdomen appears a dark spot - translucent contents of the stomach. From adult lice nymphs also differ in smaller sizes.
Below are some more photos of head lice:
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The structure of the head lice body is typical for insects, but it also has features. Her legs have pincer segments at the end, allowing the insect to easily grab a bunch of hair. The picture shows a head louse with a large increase: on its head there are small antennae, and the abdomen of the insect has uneven edges. It is interesting that the lice are underdeveloped eyes, and from their senses they rely mainly on the sense of smell.
But especially known nits are louse eggs. They are very small - just over half a millimeter in length - and are glued to the hair by a female lice. Actually, it is the nits that first of all come to your eyes, and therefore it is easiest for them to determine that a person is infected with lice.
"I did not see the lice first in the child, but their shit. A nightmare, I thought it was just some kind of rubbish, but he always appears. Such tiny black dots, that if the hair were thicker, they would not have been noticed. Started picking at Lidochka in my head - and found. First, nits on the hair, and then the lice themselves. Disgusting sight - they are so white, translucent. I do not know how other mothers after that still read something on the Internet, they will find out. I already in ten minutes bought a shampoo in the pharmacy, so I could take this muck out of my daughter ... "
Head lice in children look exactly the same as in adults. In many cases, it is from children that adults become infected with these parasites in kindergartens, schools and recreation areas.
When the lice are infected, the head often acquires a characteristic untidy appearance. No matter how insignificant head lice are, their nits with a lot of it are immediately apparent - they look like dandruff or just white sand in your hair.
The following photos show how the head lice and nits on the hair look:
From other parasites, lice differ primarily in size - mites and bedbugs are larger than them (the small larvae of bedbugs, also having translucent chitinous integuments of the body, are slightly similar to lice). Fleas, slightly similar to lice, jump well and never multiply on the head.
In general, infection with lice is sometimes more like not the presence of parasites on the head, but a kind of skin disease - parents often confuse the symptoms of the presence of lice in a child with allergies.
Below the photo shows the lice on the head of the child:
Lifestyle and Nutrition Features of Head Lice
The human head louse is a typical hematophagus . In other words, the only food suitable for this parasite is human blood. The louse sucks it, piercing the skin and the wall of the blood vessel with a special oral organ.
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Close relatives of head lice are withers in animals. They feed on both blood and secretions of the skin glands of their hosts, as well as pieces of dying skin. These parasites are generally easier to feed on blood than head lice, since most animals have wool covered areas of skin with a large number of blood vessels beneath it. On the human head, blood vessels are not everywhere equally easily accessible, and therefore lice are usually the most numerous in the neck and behind the ears.
At one time the louse sucks about 0.5 mg of blood, and should eat every four to five hours. When sucking blood, the louse injects saliva into the wound, the enzymes of which prevent blood coagulability and facilitate its flow over the insect's proboscis. These enzymes in many cases cause the appearance of characteristic blue spots in the places of lice bites, as well as allergic reactions in the victim.
The photo shows how the lice on their heads look like during a bite:
"We noticed for a long time that the little one constantly scratches his head, but thought it was dandruff or some kind of allergy. I even bought medicinal shampoos. Once on a skin in hair has noticed any grayish maculae, and has then read, that such louses leave. I started looking for - and really, it's lice. There were not many of them, but they came across, and the nits were on their hair. Before that, I never knew what the lice looked like on the head of a child, but here they themselves were sitting on their hair. "
The following video shows how the circulatory system of head lice functions (under a microscope):
The optimum temperature for lice is 31-32 ° C, which is maintained in the thick human hair. At this temperature, the louse dies without food for 2-3 days, and if the temperature drops to + 10 ° C, it can starve before 10 days
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Lice are resistant to hypoxia and can survive up to two days, falling into the water. Therefore, you can not kill the parasites by washing your hair, as well as strangling them by diving under the water.
Lice on the head of a man live permanently, without changing its location. Unlike other parasites crawling onto the human body only for feeding, the head lice have adapted to the constant presence on the head, and therefore they are very sensitive to both temperature changes and hunger strikes.
Here are a few more photos of lice and nits on your head:
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Another parasite that has passed to complete dependence on the human body is the itch mite. To solve the problem of preserving eggs, it is introduced under the skin and there it lays its eggs.
Adult lice live on the order of 30-40 days, and larvae develop about 15 days. With a decrease in the temperature of the environment, these terms increase.
Lice on the head are held mainly near the roots of the hair, in the zone of the highest temperatures. Only the females crawl up their hair for laying eggs, climbing to a height of 2-3 cm from the skin. In general, the parasite feels more confident precisely on hairs, to which it can attach very tightly. In this position, the head louse (and especially the small nymph) looks just like a small growth and is hardly noticeable.
"I do not know where all these doctors on duty in the camps are there - both my children and three of my friends came from the camp with lice. And they do not even need to be looked for in the hair - the entire hairstyle is sprinkled with snow, hanging on each nest. That's terrible. I called the organizers of the trip, pushed everyone there, said that I will complain about the whole camp to the SES. So they apologized then all in turn, from the director to the driver of the camp bus. They sent me a box of chocolates and some sort of cream from lice. No, well, not mockery? "
Reproduction of head lice
Lice lay their nits directly on the hair. Thanks to the sticky secret, which quickly hardens in the air, the egg sticks to the hair, which ensures better preservation of the future offspring. Some lice remedies, including vinegar and cranberry juice, soften the sticky substance, so it is easier to comb the nits out of the hair after such treatment.
Each female lays about 100-120 eggs for its life, approximately 4 eggs per day. Development of the egg lasts 5 days, another about 15 days grows out of the larva. The larva is very similar to an adult insect and differs from it only by the absence of genital organs and smaller body size.
The entire reproduction cycle at 32 ° C lasts about 18 days, a minimum of 16. Its duration is influenced by temperature (on short hair in the winter, the development of nits can generally be suspended, and the whole cycle can be stretched for months), and the availability of food. It is known that in people suffering from dermatological diseases of the scalp with the formation of dense crusts, the development of lice lasts longer.
The picture below shows the life cycle of the head louse:
Methods of transmission of head lice and their spread among humans
Head lice are transmitted only from person to person, usually by direct contact. It can be children's games, sex, kisses at a meeting, hugs, classes of contact sports.
It is characteristic that lice actively infect a new person, even if their number in the parasite carrier is small, and the symptoms of infection have not yet been observed. That is why parasites actively spread in children's groups: while lice on the child's head are discovered, he already has time to infect some of his friends.
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In the people there is a myth that lice at a certain stage can be under the skin and do not manifest themselves in any way until the person strongly perenervnichaet. After the "nerves" the parasites supposedly crawl out from under the skin and begin to multiply intensively. Variations of this myth are numerous, right up to the stories about cones filled with lice, and parasites in the brain itself. With the advent of new knowledge, such tales have become more "scientific" - today lice under the skin cause cancer. Of course, nothing to do with the real state of affairs such prejudices have - lice never penetrate the skin, and with the state of the human nervous system, their activity does not correlate.
Significantly less often lice are transmitted on combs, headdresses, hair bands and hoops, which are used by several people. And in very exceptional cases lice can be transmitted by water, accidentally being in a bath or pool.
The following photo shows head lice next to the invisible:
Lice can move from the lush hair of an infected person in public transport or in a crowd. Therefore, in such places should be careful.
Why are head lice dangerous?
The most common consequence of infection with lice is pediculosis. This is a set of symptoms caused by abundant bites of lice. Among such symptoms - itching, traces of bites, bluish spots on the skin, allergic reactions. In neglected cases, the person develops abscesses of the skin and even pyoderma.
Head lice very rarely carry infectious agents. In rare cases, they cause typhus and so-called trench fever, but in recent years, these diseases are associated almost exclusively with lice.
Lice do not tolerate AIDS, hepatitis and other diseases transmitted with blood and lymph.
Nevertheless, the bites of lice and pediculosis themselves are extremely unpleasant phenomena, and at the first appearance of them it is necessary to begin the fight with parasites as soon as possible. About how to do it right and not to harm your health or your child's health - read in other articles of our site in the section "How to get rid of lice."
Getting rid of lice and nits at home for 1 procedure: